1. Field of the Invention
This invention relates to a flat panel display device, and more particularly to a plasma display panel (PDP) provided with a barrier rib which can separate a discharge space of the PDP exploiting a gas charge into the discharge cell unit. Also, this invention is directed to a process of fabricating the barrier rib of the PDP.
2. Description of the Prior Art
Nowadays, there have been actively developed a flat panel display device such as a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP) and so on. In the flat panel display device, the PDP has advantages in that it provides an easiness for a manufacture of large-scale screen due to its simple structure, and that it has a light view angle more than 160xc2x0 and characteristics of lack thickness and light weight. The PDP exploits a gas discharge phenomenon to display a picture by radiating a fluorescent body of vacuum ultraviolet ray generating during a gas discharge. A typical structure of the PDP will be described with reference to FIG. 1 below.
FIG. 1 shows a structure of a discharge cell arranged in a matrix pattern in the conventional PDP. The PDP discharge cell includes an upper plate having a sustaining electrode pair 12A and 12B, an upper dielectric layer 14 and a protective film 16 that are sequentially formed on an upper substrate 10, and a lower plate having an address electrode 20, a lower dielectric layer 22, a barrier rib 24 and a fluorescent body layer that are sequentially formed on a lower substrate 18. The upper substrate 10 is spaced in parallel from the lower substrate 18 by the barrier rib 24. The sustaining electrode pair included in the upper plate consists of a scanning/sustaining electrode 12A and a sustaining electrode 12B. The scanning/sustaining electrode 12A is responsible for applying a scanning signal for an address discharge and a sustaining signal for a sustained discharge, etc. On the other hand, the sustaining electrode 12B is responsible for applying a sustaining signal for a sustained discharge, etc. The upper dielectric layer 14 is formed on the upper substrate 10 on which the sustaining electrode pair 12A and 12B is provided, thereby accumulating an electric charge. The protective film 16 is coated on the surface of the upper dielectric layer 14. A MgO film is usually used as the protective film 16. The protective film 16 protects the upper dielectric layer 14 from the sputtering phenomenon of plasma articles so that it may prolong a life of PDP and improve an emission efficiency of secondary electrons. Also, the protective film 16 reduces a variation in the discharge characteristic of a refractory metal due to a contamination of oxide. The address electrode 20 included in the lower plate is formed on the lower substrate 18 in such a manner to be crossed with the sustaining electrode pair 12A and 12B. The address electrode 20 serves to apply a data signal for the address discharge. The lower dielectric layer 22 is formed on the lower substrate 18 on which the address electrode 20 is provided. The barrier rib 24 is arranged in parallel to the address electrode 20 on the lower dielectric layer 22. The barrier rib 24 serves to provide a stripe-type discharge space at the inner side of the discharge cell so as to shield electrical and optical interference between the adjacent discharge cells. Also, the barrier rib 24 serves to support the upper substrate 10 and the lower substrate 18. The fluorescent body layer 26 is coated on the surfaces of the lower dielectric layer 22 and the barrier rib 24 to generate a red, green, or blue visible ray. Further, an inactive gas for the gas discharge is sealed into the discharge space. The PDP discharge cell having a structure as described above maintains a discharge by a face discharge between the sustaining electrode pair 12A and 12B after being selected by an opposite discharge between the address electrode 20 and the scanning/sustaining electrode 12A. In the PDP discharge cell, the fluorescent body 26 is radiated by an ultraviolet ray generated during the sustained discharge, thereby emitting a visible light to the outer side of the discharge cell. As a result, the PDP with the discharge cells displays a picture.
FIG. 2 shows a PDP device including the discharge cell shown in FIG. 1. Referring to FIG. 2, the barrier rib 24 plays an important role of providing a stripe-type discharge space to prevent electrical and optical interference between the adjacent discharge spaces. In this case, the conventional barrier rib 24 has a width of about 100 xcexcm and a height of about 200 xcexcm, and it is mainly made from a ceramic or a glass-ceramics. However, the conventional stripe-type barrier rib 24 has a problem in that, since it separates the discharge space only into the column line unit without separating the same into the row line unit, it fails to shield electrical and optical interference between the row lines. In other words, in the conventional barrier rib 24 cannot shut out electrical and optical interference between the picture elements because a discharge space is not separated for each picture element. Further, a PDP device including the conventional stripe-type barrier rib 24 has a drawback in that it has a relatively low radiation efficiency because it utilizes only the fluorescent body layer 26 coated on each face of the barrier rib 24 and the surface of the lower dielectric layer 22.
In addition, the conventional barrier rib 24 is formed by exploiting the screen printing technique, the sand blast technique, the additive technique or the like. However, such methods of fabricating the barrier rib have basic problems in that a fabrication process is complicated and a large amount of materials are wasted.
FIG. 3a to FIG. 3d are sectional views for representing a process of fabricating the barrier rib making use of the screen printing technique step by step. Referring now to FIG. 3a, there is shown a structure in which the lower dielectric layer 22 and the glass paste patterns 28 are disposed on the lower substrate 18 in turn. The glass paste patterns 28 are formed by coating a glass paste prepared by mixing glass powder, which is mixed by the parent glass and the filler, with an organic vehicle on the lower dielectric layer 22 at a desired thickness using the screen printing technique and thereafter by drying the same during a desired time. Then, a process of forming the glass paste patterns 28 as mentioned above is repeatedly performed about seven to eight times as shown in FIG. 3b and FIG. 3c. As a result, the glass paste patterns 28 are disposed into a desired height, for example, of 150 to 200 xcexcm. The glass paste patterns 28 disposed in this manner are calcined to provide the barrier ribs 24 having a desired height on the lower dielectric layer 22 as shown in FIG. 3d. 
Such a screen printing method has an advantage in that the process is simple and the fabrication cost is low. However, the screen printing method has a problem in that a lot of time is required because it needs procedures for performing a position adjustment of the screen and the lower substrate 18 and for repeating the printing and the drying several times. In addition, the screen printing method is not suitable for the fabrication of a barrier rib for a high resolution PDP because a position between the screen and the lower substrate go amiss during the repeated work.
FIG. 4a to FIG. 4f are sectional views for representing a process of fabricating the barrier rib making use of the sand blast technique. After a glass paste 30 is coated on the lower dielectric layer 22 formed on the lower substrate 18 as shown in FIG. 4a, a photo resistor 32 is coated on the glass paste 30 as shown in FIG. 4b. Next, as shown in FIG. 4c, mask patterns 34 are positioned on the photo resistor 32 which is exposed to a light through openings of the mask patterns 34 in turn. Subsequently, after the mask patterns 34 are removed, a non-exposed portion of the photo resistor 32 is removed to form photo resistor patterns 32A as shown in FIG. 4d. Then, glass paste patterns 30A are formed in the same shape as the photo resister patterns 32A as shown in FIG. 4e by removing the exposed glass paste 30 through the photo resistor patterns 32A using the sand blast technique. Consequently, the barrier ribs 24 are provided on the lower dielectric layer 22 as shown in FIG. 4f by calcining the glass paste patterns 30A after removing the photo resistor patterns 32A.
Such a sand blast method has an advantage in that the formation of fine barrier ribs is possible and it is suitable for manufacturing a large dimension of substrate. However, the sand blast method has problems in that a lot of cost is required for the facilities investment, that the fabrication process is complicated, and that a lot of materials are wasted. Also, the sand blast method gives rise to a crack of the substrate at the time of calcining because physical impact is applied to the substrate by the sand blast.
FIG. 5a to FIG. 5e are sectional views for representing a process of fabricating the barrier rib making use of the additive technique step by step. As shown in FIG. 5a, a photo resistor 38 is coated on the lower dielectric layer 22 disposed on the lower substrate 18. Then, as shown in FIG. 5b, mask patterns 40 are positioned on the photo resistor 38 which is exposed to a light through the mask patterns 40. Subsequently, the mask patterns 40 are removed and then the exposed portion of the photo resistor 38 is removed to thereby form photo resistor patterns 38A as shown in FIG. 5c. Next, as shown in FIG. 5d, glass pastes 30 are coated between the photo resistor patterns 38A and then dried. Consequently, the barrier ribs 24 are provided on the lower dielectric layer 22 as shown in FIG. 6e by removing the photo resistor patterns 38A and thereafter by calcining the glass paste 30.
Such an additive method has an advantage in that the formation of fine barrier ribs is possible and it is suitable for manufacturing a large dimension of substrate. However, the additive method has problems in that, when the glass paste 40 having a height of more than 100 xcexcm is coated, a lot of fabrication time is required, and the coated glass paste 40 is collapsed or a crack is generated at the barrier ribs 24 at the time of calcining. Also, the additive method requires the development of a technique that can cleanly eliminate a sensitive film remained after the calcining.
Accordingly, it is an object of the present invention to provide a fabrication for forming barrier ribs for a plasma display panel (PDP), which is solve the problems as described above of the prior art.
Another object of the present invention is to provide a plasma display panel (PDP) wherein it includes a barrier rib with a lattice structure to separate a discharge space for each picture element, thereby shielding electrical and optical interference.
Still another object of the present invention is to provide a PDP wherein it includes a barrier rib with a lattice structure to increase a coated area of a fluorescent body layer, thereby improving the radiation efficiency of the PDP device.
Still another object of the present invention is to provide a PDP wherein it uses a barrier rib as a sustaining electrode to reduce the number of construction elements of an upper plate, thereby improving a transmitted light amount.
Still another object of the present invention is to provide a mold for fabricating a barrier rib that is adaptive for the fabrication of a barrier rib with a lattice structure.
Still another object of the present invention is to provide a method of fabricating a barrier rib for a PDP wherein a barrier rib is formed by means of the electro plating, thereby simplifying a fabrication process of the PDP barrier rib.
In order to achieve these and other objects of the invention, a plasma display panel according to one aspect of the present invention includes a first electrode for applying a scanning signal and a sustaining signal; a second electrode for applying a image data signal; a first substrate at which the first electrode is defined; a second substrate at which the second electrode is defined; and a barrier rib, being formed between the first substrate and the second substrate, for providing a discharge space closed on all sides.
A mold for fabricating a barrier rib in a plasma display panel according to another aspect of the present invention includes a body having a plating solution inlet formed on one side thereof; and a pattern formed on other side of the body to form the barrier rib.
A method of fabricating a barrier rib in a plasma display panel according to still another aspect of the present invention has the step of forming a metal barrier rib by using an electric plating technique.
Further, a method of fabricating a barrier rib in a plasma display panel according to still another aspect of the present invention includes the steps of forming a metal seed layer on a first substrate; attaching a barrier rib fabricating mold prepared separately onto the metal seed layer; filling the mold with a plating liquid using an electric plating technique to form the barrier rib; and separating the mold from the barrier rib and removing the exposed metal seed layer.